Teaching Case

Case 1:

An eleven-year-old girl presents with restrictive eating habits and recurrent vomiting. On examination, she had alopecia, was underweight and had a large upper abdominal mass (Figure 1A).

Case 2:

A seven-year-old girl with a history of trichotillophagia presents with a 7-month history of intermittent abdominal distension, vomiting and watery diarrhoea.

Case 1:

Radiograph (Figure 1B): There is paucity of bowel gas in the central abdomen; a lobulated opacity with mottled gas pattern is displacing the colon peripherally.

Sonography (Figure 1C): An echogenic mass is seen just under the abdominal wall, producing significant acoustic shadowing and twinkling artefact.

CT (Figure 1D): A large mass with mottled gas pattern is seen distending the stomach.

Case 2:

Radiograph (Figure 2A): Features of intestinal obstruction are seen. Intraluminal mottled gas lucencies are projected over the expected location of bezoars in the lower abdomen.

Sonography (Figure 2B): Distended bowel loops containing echogenic contents seen; the contents in the ileum demonstrate acoustic shadowing. Some free fluid noted.

CT (Figure 2C): Transition point seen in the right lower quadrant, distal to two intraluminal masses with mottled gas pattern. Small bowel faeces proximal to the transition point suggests delayed intestinal transit. Floating fat-density debris sign seen (Figure 2D).

Background

The word "bezoar" comes from the Persian word pādzahr - meaning “antidote”, as they were thought to neutralise poisons [1]. They are aggregates of undigested substance within the gastrointestinal tract and can compose of plant fibres (phytobezoars), hair (trichobezoars), milk protein (lactobezoars) or medication (pharmacobezoars). They tend to form in the stomach as the material which forms the matrix of the bezoar tend to accumulate in the mucosal folds of the stomach with slow gastric emptying [2]. These bezoars can grow to a larger size before they cause obstructive or mass effect symptoms. In the small bowel, bezoars tend to be impacted in the ileum, the narrowest part of the small bowels and hence, tend to become symptomatic at a smaller size.

Here, we demonstrate the similar radiological features of trichobezoars found in two different positions on three different modalities. The two cases are of similar aetiology but demonstrate different radiological findings due to the different locations of the bezoar.

Imaging Perspective

Trichobezoars do not demonstrate any specific findings on radiographs, however, if they are as significantly large as in our first case, the mass effect displacing bowel loops can be appreciated. Although it can be appreciated retrospectively, the mottled gas appearance of bezoars that is traditionally described [3] can be difficult to distinguish from normal bowel gas.

Sonographically, they are seen as echogenic intraluminal contents with significant acoustic shadowing and twinkling artefact. This is distinct from faecal material, which tends to be softer and more movable; they cannot produce the rough surface for twinkling artefacts or the high acoustic impedance for posterior acoustic shadows [4].

On CT, they are seen as intraluminal masses with well-defined, encapsulated mottled gas densities seen within. The floating fat density described by Delabrousse et al. [5] can also be appreciated (Figure 2D), this fat-density debris floating in the dilated bowel loops proximal to the obstructive lesion is due to the sum of the tissue density of the debris and the very negative density of the air in which it is trapped.

Take-Home Message / Teaching Points

Both cases emphasise the importance of clinical correlation. The non-specificity of the clinical symptoms and radiological findings makes the diagnosis of trichobezoars an elusive conundrum and the history of trichotillophagia offered by the parents in both cases was critical in the diagnostic process.

Statement of obtained patient consent

Written informed patient consent for publication has been obtained.